public class e3_6{
  public static void main(String args[]){
   double sum=0,item=1;
    int i=1,n=20;
	while(i<=n) {
	 sum=sum+item;
	i=i+1;
	item = item*(1.0/i);
	}
	System.out.println("sum="+sum);
  }
}
